Thread-cutting mechanism.



1.]. SULLIVAN & A. F. FIFIELD.

THREAD CUTTING MECHANISM. 7

APPLICATION FILED NOV. 14. 1912.

Patented Aug. 31, 1915 a SHEETSSHEET 1.

EL N- 7850 WlT/VESSES: I EII/TOH- BY I l. l. SULLIVAN & A. F. FIFlELU.

THREAD CUTTING MECHANISM.

APPLICATION FILED NOV. 14, 19|2.

31 9 1L 5 1 735., Patented Aug. 31, 1915.

3 SHEET3SHEET 2 W/TA/ESSES: //V A/ B3 E4 2335 BY if e 1.]. SULLIVAN & A.F. FEHELD.

THREAD CUTTING MECHANISM.

APPLICATION FILED NOV. 14, 1912.

Patented Aug. 31, 1915.

3 SHEETSSHEET 3.

WITNESSES: fill/E/VTORS A q 9 M 'u afar JQHN J. SULLIVAN, G1 IPSWICH,MASSACHUSETTS, AND ALBERT E FIEIEL'D, {BF BRIDGElORT, CONNECTICUT,ASSIGNORS TO THE SINGER MANUFACTURING: CiJll L THREAD-CUTTINGMECL'IANESM.

Specification of Letters Eatent.

ted

Patch Ang. 2331, 19

Application filed. November 14, 1M2. Serial No. 731,242.

- companying drawings.

While the present invention is adapted for application to various typesof sewing machines, it is especially designed for embodiment in buttonsewing machines of the type shown in the United States patent to J. J.Sullivan and E. B. Allen No. 742,366, of October 27, 1903, and it hasfor one of its chief objects to simplify and to render more efiectivethe class of thread-cutting mechanism to which said patent is directed.

Certain other objects will appear in connection with the followingdescription.

As preferably constructed, the cutting device is composed ofoverlappingthread-cutting and -nipping blades slidingly mounted within atransverse guideway of the presserfoot and whose extremity at the needleaperture affords shoulders coiiperating with the operative edges of suchblades in the niping and severing actions upon the needlethread. Mountedupon a fixed fulcrum of the machine is a plural-armed lever having onearm connected by a link with the cutting and nipping blades and anotherarm operatively connected with the controlling cam for imparting lateraljogging movements to the needle and'controlling the period of action ofthe stitclrforming mechanism through the usual stop-motion device. Bymeans of the controlling cam operative movements are imparted to saidlever for retracting the blades from nipping and cutting or operativeposition into a position at the opposite side of the needle-path inreadiness for a succeeding nipping and cutting action; and after thethread leading from the final stitch of a group has been looselyembraced by the blades. the action of automatic presser-foot liftingmeans thereon through a connection with a third arm of the plural-armedlever imparts to the nipping andcutting blades :1 quick operativemovement while the needle is raised for nipping and cutting the thread.

'lhe nipping blade is preferably provided in its operative or nippingface with one or more indentations into which the thread is compressedbetween such face and the adjacent face of the guide-channel so as toform protruding parts of the partially crushed thread which look thesame in position in addition to the frictional action of the partsbetween which it is thus clamped.

In the drawings, Figure 1 is a rear side elevation of a Singer buttonsewer embodying the present improvements, and Fig. 2 a front end view ofthe same. Fig. 3 is a perspective view of a portion of the stopmotiondevice, showing the operative connection between the same and thepresserfoot lifting mechanism. Fig. i is a side elevation of the cuttingmechanism and certain parts connected therewith, and Fig. 5 an endelevation of a portion of the cutter-actuating mechanism.- Fig. 6 is aperspective view of the presser-foot and the cutting elements positionedtherein for a cutting action. Fig. 7 is an enlarged sectional elevationshowing the action of the cutting device upon the thread. Figs. 8 and 9are perspective views of the overlapping cutting and nipping bladestaken respectively from the upper and lower sides. As representedherein, the frame of the machine comprises a hollow standard 1 withlaterally extending work-supporting arm 2 and overhanging bracket-arm 3in which is journaled the main-shaft 4 having upon its rear end theloose belt-pulley 5 and fast pulley 6 to which is attached the stoppingcam 7 formed with the eccentric periphery 8 terminating in the notch 9.The head of the bracket-arm has mounted therein the laterally joggingneedle-bar frame 10 and in which is journaled the needle-bar 11 carryingthe needle 12 and connected by means of the pitman 13 with thecrank-stud 14 upon the take-up cam-cylinder 15 secured upon themain-shaft l and from which the needle derives its reciprocatingmovements. The needle-bar frame is connected by means of the pitman 16and other connections with the suitably grooved controlling cam 17 whichimparts lateral jogging movements to the needle for production offastening overseam stitches.

Within a suitable race 18 applied to tne work-supporting arm. 2 ismounted the shut tle l9 cooperating with the reciprocating and laterallyjogging needle 12 and provided. with the usual bobbin-case 28 for thelower thread Mounted within the head of the bracketarm is the usualpresser-bar :21 normally pressed downwardly by means of a spring 22interposed between the lower end of the bushing 23 and. the collar 2%fixed thereon and provided with the lateral lug 25 and with ,a secondforked. lug 26 embracing the guide-pin 27. Secured by means of thefastening screw 28 upon the lower end of the presser-bar is the shank 29of the pressen foot 30 formed in its forward portion with theneedle-slot or aperture 31 and at one side thereof with the lateralextension 32 which is shown provided in its lower face with thetransverse guide-channel 33 closed in its lower side by means of theplate 34 secured thereto by screws 35 The presser-foot is shown cut awayrearward of the needleaperture 31 to form the transverse buttonguidingseat 38 Mounted within the guide channel or guideway 33 is a compoundcutting and nipping element comprising two overlapping blades 37 and 38which are normally reversely arched, as represented in Figs. 8 and 9 andformed at the rearward end with alined apertures 39. At the oppositeends, these blades are provided with lateral hooked extensions a0 andll'having operative shoulders 40 and ll upon the inner edges of thefaces farthest apart. In practice, the edge 40' of the nipping member4C0, which is arranged slightly in advance of the edge 4:1, is slightlyrounded so as to avoid injuring the thread nipped between. the same andthe correspondingly formed operative shoulder 32 of the channel 33,while the edge 41 is sharpened, as represented in Fig 7, so as toproduce a shear-cut in conjunction with the opposed shoulder 34 of thechannel 33. The nipping element 40 is shown provided in its upper orouter face with theniclrs or indentations 422 into which a portion ofthe needle-thread n is compressed; in the nippingoperation, asrepresented in Fig 7 to insure against pulling out of the cut end ofthread leading to the needle in the production of the initial stitch ofa group succeeding a nipping and cutting action,

The rearward ends of the blades 37 and 38 are secured by means of theclamp-screw 4-3 within a depressed seat forined therefor in theblochwhich is providedwith the spaced and s 'iertured cars to between whichis pivotally secured by means of the screw pin it one end of a "r 4:?whose apertured opposite end is connected by means of the screw-pin $8with "he d pending arm 49 of an angle-lover hay has 50 and a eral arm 51carrying t ie roller-stud 52., The hub 50 of the angle-lever ea Si. issecured by means of the set-screw 53 upon one end of the rocking pin 5djournaled in the bearing boss 55 of the bracket-arm 3 and having securedupon its opposite end by means of the set-screw 56 the hub 57' of anupwardly extending arm 58 carrying a roller-stud 59 which enters thecam-groove 60 of the cone trolling cam 17. The members 49 51 and '58being rigidly connected together constitute a plural-armed leverfulcrunied upon the bearing boss 55w Mounted upon the fulcrum-stud 61sustained by the bracket-arm 3 is the presserfoot lifting rock-levercomprising the forwardly extending arm 62 projecting beneath the lug 25of the presser-barcollar 24 and the rearwardly extending arm 63 carryingthe lateral stud-pin 64: which is embraced by the forked forward end 65of the arm 66 of a rock-lever mounted upon the fixed fulcrum-stud 67 andhaving the rearwardly extending arm 68 provided with the laterally odsetperforated boss 69. The boss 69 has fitted Within its socket theplunger-pin 78 whose reduced rearward end is provided with thethrust-nut 71 and jam-nut 72 to sustain the thrust of the spring 73encircling the same and interposed between the inner end of the socketand the enlarged forward end of the pin.

The plunger-pin is adapted to engage the top and adjacent inclined sideof the collar 74: fixed upon theplunger-bar 75 which is journaled in therocking stop-lever 76' fulcrunied at 77 upon the bracket 78 su tained bythe standard L interposed between the bearing boss 76' of the lever 76and the collar 7% 1s a spring 79 which forces the upper end oftheplunger-bar 75 into operative relation with the periphery of thestopping cam 7. The plunger-bar is normally maintained in operativerelation with the stopping cam by means of a spring 80 interposedbetween the upper portion of the stop-lever 7G and the standard 1, andis shifted laterally in. opposition to such spring for disengagement ofthe plunger-bar and stopping earn by means of a lateral arm 81 of thestop-lever whose apertured outer end is entered by the headed upperextremity of the treadle-rod 82.

The arm 81 carries a laterally projecting stud 83 embraced by the forkedextremity 84c of the lateral arm 85 of an angle-lever mounted upon thefulcrum screw-stud 86 and having the upwardly projecting arm 87 carryinga roller-stud 88 adapted to rest in contact with the end 88 of thecontrolling cam 17. The extremity 89 of the earn 17 affords astop-shoulder to maintain the angle-lever 85 87 in position to hold thestoplever 78 retracted for continuing'the plunger-bar "Z5 disengagedfrom the stopping the controling cam 17, this notch a'iio a clearancerecess which is J. 1 re o en red y the roller-stud under the action ofthe spring upon and through the stople er 76, t permitting theplunger-bar 75 unis to assume a position in register with the lower partof the perohery of the cam 7 and to be forced downwardly by the sameuntil permitted to rise into the notch 9 under the action of the springY9,

The collar 74 is laterally retracted from 1 e plunger-pin 0 when thestop-lever is 'ted to the stopping elements nd throw the belt from theloose to the fast ul ey, but when the stop-lever returns to pingposition, the collar 7 assumes operative relation wi h the plunger-pinT0 with its upper or operative face above the ere As the plungerdescends under the tion of the peripheral portion of the cam t sin T0 isforced. inwardly by engagethe inclined adjacent side portion. collaruntil the top of the latter descends beneath it, when the pin snaps outabove the same, and in the ascent of the plunger-bar 75 to enter thecamnotch 9 the collar 74 forcibly engages the plunger-pin i0 and tiltsthe rock-lever (36 68 which produces a similar elfect upon therock-lever 62 and lifts the Presser-bar and with it the presser-foot inopposition to the spring The tilting of the rock-lever arm 63 by themeans just described causes the latters forcible engagement with therollerstud 52 of the arm 51 which causes the final step of the operativemovement of the nipping and cutting blades 3? and 38, a clearanceportion (30 being formed in the cam-groove (30 to permit the slightlateral movement of the roller-stud 59 produced by the presser-footlifting mechanism.

As represented in Figs. 1, 2 and 7, the mechanism is in stoppingposition just succeeding a nipping and cutting action at the completionof a button-fastening operation. Upon the actuation of the treadle-rod82, the stop-lever 76 is rocked to start the machine, and thepresserefoot lowered upon the throatplate through the disengagement ofthe collar 7 1- with the plungerpin 70, the treadlc-rod being maintainedlowered until the notch 89' has moved out of register with theroller-stud 88 when the latter is permitted to rest against thestop-member 89 to maintain the stop-lever in running position for acomplete stitching cycle. The nipping and cutting elements 40 and 41 arenot disturbed until the completion of the first few stitches of thecycle, after which the action of the cam-groove 60 upon the roller-stud59 causes the rocking of the operating lever 49 51 58 to shift theoperative elements 40 and. s1 across the needle-path while the needle israised between. stitches to direct the lead of the needle-thread intermediate such elements and the adjacent end of the channel or guideway33.

During the final rotation of the mainshaft in a stitching cycle, theportion 60" of the arm-groove 60 acts upon the rollerstud o9 impart apartial retractive move ment to the nipping and cutting elements so asto loosely embrace the needle-thread, as represented in Fig 6,presenting thereafter to the roller-stud widened. portion (30 acrosswhich it is shifted by a quick movement in the final nipping and cuttingstage of the operation under the action of the pr sser-foot liftingmechanismcoinci dent with the arrest of the main-shaft by thestop-motion device. lit the end of the stitching operation, the take-uplever 91 is preferably in its highest position, so that there will be nostrain upon the nipped needle-thread at the beginning of the initialstitch of the succeeding group. 7

l fe have not described herein the button. presenting means shown in theaccompanying drawings, as they form the subject of a pending applicationfiled simultaneously herewith.

lala 'ing thus set forth the nature of the invention, what we claimherein is 1. in a sewing machine, the combination with stitch-formingmechanism, and a worksupport, of a presser'foot, a thread-cutting devicesustained thereby, a connection between the presser-foot and thethread-cutting device through which operative movement is imparted tothe latter, a spring for lifting the presser-foot, and a cam forcompressing said spring and controlling its action in lifting thepresser-foot.

2. In a sewing machine, the combination with stitch-forming mechanism,and a work-support, of a presser-foot, a threadcutting device sustainedthereby, lifting means for the presser-foot comprising a spring and acam for compressing said spring and controlling its action in liftingthe presser-foot, and an operative connection between the lifting meansand the thread-cutting device whereby the movement of the lifting meansis transmitted to the thread-cutter.

3. In a sewing machine, the combination with stitch-forming mechanism,and a worksupport, of a presser-foot formed with a transverse channel, athread-cutting device comprising a blade slidingly mounted within saidchannel and having an operative portion movable across the range ofaction of the stitch-forming mechanism, presser foot lifting meanscomprising a spring and a cam for compressing said spring andcontrolling its action in lifting the presser-foot, and a connectionbetween the presser-foot lifting means and said blade whereby movementof the lifting means is transmitted to the thread-cutter.

4. In a sewing machine, the combination with stitclrforming mechanism,and a work-support, of a presser-foot, a thread cutting device includinga severing member, a controlling cam for determining the period ofaction of the stitch-forming mechanism, a connection between thecontrollingcam and the thread-cutting device for positioning thesevering member preparatory to a cutting action, presser-foot liftingmeans, and a connection between said lifting means and thethread-cutting device for imparting to said severing member a secondmovement in the same direction to cut the thread.

5. In a sewing machine, the combination with stitch-forming mechanism,and a work-support, of a presser-foot formed with a transverse channel,a thread-cutting device comprising a blade slidingly mounted within saidchannel and having an operative portion movable across the range ofaction of the stitchiorming mechanism, a swinging operating lever, alink having pivotal connections with said blade and lever, presser-footlifting means, and an operative connection between said lifting meansand said lever.

6. In a sewing machine, the combination with stitch-forming mechanism,and a work-support, of a presser-foot formed with a transverse channel,a thread-cutting device comprising a blade slidingly mounted within saidchannel and having an operative portion movable across the range ofaction of the stitch-forming mechanism, presser-foot lifting means, aplural-armed operating lever having one arm connected with said blade, asecond arm connected with and actuated by a cam, and a third armoperatively connected with the presser-foot lifting means.

7. In a sewing machine, the combination with stitch-forming mechanism,of a threadcutting device including a blade movable across the range ofaction of the stitchi'orming mechanism, a controlling cam, a connectionbetween said controlling cam and said blade from which the latterderives successively a single retractive movement from operativeposition and a partial advance movement toward the same, and means timedin its action by a connection with said controlling cam for imparting tosaid blade a further advance movement into initial. operative position.

stop-motion device for completing the ad Vance of said knife to initialoperative position.

9. In a sewing machine, the combination with stitch-forming mechanism,and a worksupport, of a presser-toot formed with a transverse channel, athread-cutting and nipping element slidingly mounted within said channeland having an operative portion movable across the range of action ofthe stitch-forming mechanism and having one face formed with anindentation and adapted to act in conjunction with a wall of suchchannel in nipping the thread, and means for imparting operativemovements to said blade.

10. In a sewing machine, the combination with stitch-forming mechanismincluding a reciprocating needle, and a work-clamping member, of athread-cutting and nipping blade formed with a lateral extension movableacross the needle-path and provided with thread-cutting and nippingedges, cut ting and nipping elements disposed permanently at one side ofthe needle-path for cooperation with the cutting and nipping edges ofthe extension of said blade, a support for said blade and thecooperating cutting and nipping elements sustained by and movable towardand from the work with said work-clamping member and provided with aguideway in which said blade is mounted for endwise rectilinearreciprocation, a rock-lever mounted upon a fixed fulcrum, a linkconnection between said rocklever and said blade for impartingrectilinear movements to the latter, and means acting at intervalscomprising a plurality of stitch-forming cycles for imparting reciprocaloperative movements to said bladerelatively to said cooperatingthread-cutting and nipping elements.

11. In a sewing machine, the combination with stitch-forming mechanism,of a threadcutting and -nipping device including a longitudinallyreciprocating blade formed with a lateral extension movable across therange of action of the stitch-forming mechanism and havingthread-cutting and -nipping edges, a support provided with a guideway inwhich said blade is mounted for endwise rectilinear reciprocation,cutting and nipping elements disposed permanently at one side of thestitch-forming mechanism for cooperation with the cutting and nippingedges of the extension of said blade, actuating means for imparting tosaid blade its memes operative movements for action upon the names tothis specification, in the presence of thrgad, and meansactinfiindepemiiantlyl (if two subscribing witnesses. v sai actuatingmeans wit in a perio inc u ing at least one complete stitch-forming P 6cycle for imparting to said blade retractive movements from operativerelation with the Witnesses:

relatively fixed. elements.- GEO. M EVANS,

In testimony whereof, we have siedl our STANLEY N. Smrrn.

